I don't think he played enough to cramp. He didn't even play a half.
As a former collegiate athlete that's somewhat out of shape currently, I still sometimes catch a cramp after 5 minutes of crazy-positioned secks in my ice-cold 71 degree house, without breaking much of a sweat. AND I drink a gallon of water a day.
Tua, being the well-conditioned affuleet dat he is, had been participating in athletic movement (between warm-ups and live game action) for well over 1.5 hrs with minimal rest between series. In 90 degree heat, sweating profusely. So if he missed just a few ounces of hydration, he was gonna cramp.
Mack Wilson was also catching cramps in the 1st half.